Gradient isotopique le long de l'arc des Nouvelles Hébrides (Vanuatu, Pacifique sud-ouest); collision de la zone d'Entrecasteaux et hétérogénéité des sources mantelliques  [Isotopic gradient along the New Hebrides Arc (Vanuatu, Southwest Pacific); collision of the d'Entrecasteaux Zone and heterogeneity of mantle sources]

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doi: 10.1016/S1251-8050(97)87453-8
Alternate Title:Isotopic gradient along the New Hebrides Arc (Vanuatu, Southwest Pacific); collision of the d'Entrecasteaux Zone and heterogeneity of mantle sources
Authors:Laporte, C.; Briqueu, L.; Cluzel, D.; Eissen, J. P.
Author Affiliations:Primary:
Université Française du Pacifique, Noumea, New Caledonia
Other:
Université de Montpellier II, Montpellier, France
ORSTOM, Plouzane, France
Volume Title:Comptes Rendus de l'Académie des Sciences, Série II. Sciences de la Terre et des Planètes
Source:Comptes Rendus de l'Académie des Sciences, Série II. Sciences de la Terre et des Planètes, 326(2), p.101-106. Publisher: Gauthier-Villars, Montrouge, France. ISSN: 1251-8050
Publication Date:1998
Note:In French with English summary. 17 refs.; 1 table
Summary:The recent volcanic activity of the New Hebrides arc (Vanuatu) has been influenced by the collision with the d'Entrecasteaux Zone, the composition of which remains uncertain. New trace elements and isotopic data from these lavas allow previous interpretations of compositional gradients along the arc to be qualified. The geochemical compositions of lavas display abrupt changes from calc-alkaline compositions straight in front of the collision zone, to arc-tholeiite on both sides. In contrast, isotopic compositions display a progressive variation related to less and less enriched sources away from the collision zone, evolving toward 'normal' MORB-type sources. Such a trend suggests that two types of contamination have occurred: in front of the collision zone, a magmatic contamination due to the subduction of an older lithosphere (206Pb/204Pb trend) and contamination by an "enriched-type" mantle component (Dupal feature).
Sections:Geochemistry
Subsections:Igneous rocks
Subjects:Alkaline earth metals; Calc-alkalic composition; Chemical composition; Heterogeneity; Island arcs; Isotope ratios; Isotopes; Lava; Lead; Magma contamination; Mantle; Metals; Nd-144/Nd-143; Neodymium; Pb-206/Pb-204; Radioactive isotopes; Rare earths; Sr-87/Sr-86; Stable isotopes; Strontium; Trace elements; Melanesia; Oceania; Pacific Ocean; Vanuatu; Entrecasteaux Zone
Abstract Numbers:99M/556
Record ID:1998040846
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from PASCAL, Institute de l'Information Scientifique et Technique, Vandoeuvre-les-Nancy, France
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